Tell me your thoughts

[6speedsd]

Truck is a 2003 with the 6.0

Been having cranking issues. For the longest we thought it was stiction...plugged in she would fire right up. Truck runs perfect at idle, even on the cold days, but lately developed a miss with a load in it. Then in the last week it's getting even hard to crank when the truck is warm.

Ran AE this morning. Truck wasn't plugged in last night. Temps in the high teens. Turned over 3 times an fired, chugged for a second and went dead. Big cloud of smoke out the tailpipe. Turned over again for 10-15 seconds before it fired and ran. Here are some of the numbers... No internet at home so I can't post the file.

Right before it fired...
Rpms 117
ICP 48.15 psi, desired 2299, ICP voltage .29, IPR 84.7%

Soon as it started running..
Rpms 1157
ICP 1913, desired 1534, voltage 2.1, IPR 52%


I let it run a couple mins then shut it off and cranked again. ICP went up to 1500psi again before it fired, IPR was again high at around 77%. Voltage this time went to almost 5v until it fired.

ICP actual never lags behind desired, and it is holding pretty stable at idle. ICP voltage is hanging between 1-2v.

Been running for about 15mins now. ICP is holding in the 600's, IPR about 22%.

I wish I could post the file...probably would make more sense than me just telling numbers. I assume we are looking at an oil pressure problem here?


Sent from my iPhone using Tapatalk

 

[6speedsd]

After posting, I shut it off and fired again. Op temps are up. IPR went to 65% before I fired. ICP was just over 1000. Hpop getting weak?


Codes before I cranked this morning...
#8 cyl contribution
ICP low
Something about cam sensor, but I forget what it was.

Cleared them, now all I'm getting is P2617 CKP output circuit open.
Sent from my iPhone using Tapatalk

 

[6speedsd]

Shut it off, let it sit for 5 mins, then got a 10-15 second crank time before it fired.

ICP went up to over 1500psi, IPR back up close to 70%


Sent from my iPhone using Tapatalk

 

[Mdub707]

Try unplugging your ICP sensor and doing the start again. Your actual is higher than desired, which is ODD, but not impossible, I have seen this a few other times.

 

[6speedsd]

A bad ICP will cause IPR to fully open like that?


Sent from my iPhone using Tapatalk

 

[Snake]

Did you take the tune out before beginning your troubleshooting?

.

 

[6speedsd]

This is my dad's truck, not mine. Truck has never been tuned.


Sent from my iPhone using Tapatalk

 

[Mdub707]

Any idea if the ICP sensor or pig tail have ever been replaced on this? It's very common on 03's and early 04's for causing issues, but like I said it's NOT very common to see ICP actual higher than desired.

 

[6speedsd]

Sensor has been replaced several years back. I doubt the pigtail was replaced though.

I want to say on mine (05), actual runs higher than desired.


Sent from my iPhone using Tapatalk

 

[6speedsd]

A bad ICP will cause IPR to fully open like that?


Sent from my iPhone using Tapatalk

bump

 

[Mdub707]

Actual and desired should be really close together though. Even if it was higher, it shouldn't be 400psi higher. Have you tried pulling the IPR valve to see what it looks like?

 

[6speedsd]

I haven't done anything to it yet. I will be tearing the top half off at some point... has an oil leak up top somewhere that I need to find. Just trying to get an idea what could be the issue before I started working on the thing. Don't want to tear it apart and just start throwing parts at it. I'd hate to tear it down and replace an IPR only to find out that didn't fix it and have to tear it down again. I just need to get it figured out before about March, because once that gets here, we will be working 70-80hrs a week, and it'll be on the road 7 days a week, and we can't have it down. Well we could use mine, but he won't do that. And I'm not about to let him pay out the arse for the dealer to fix it.

Sucks that on the 03, ICP is under the turbo.

 

[6speedsd]

Once the truck warms up a little, actual and desired stay within 100psi of eachother. It's just really off during cold engine starts, and until it warms up for a couple minutes.

If the truck is plugged up the night before, it'll usually crank pretty quick. I haven't watched the numbers when it's plugged in. I know #8 injector has pretty bad stiction, but that shouldn't cause those numbers to be so far off, right?

One day last week, we drove it to where we were working.... it sat for maybe 3 hours. temps were in the low 40's I think. went to leave, and it wouldn't start. Tried for nearly 10 minutes before it fired. Wouldn't hit a lick. Had to hook jumper cables up because he nearly drained the batteries. Then, all of a sudden, it fired. It'll be like you just flip a switch or something. It'll turn over and over and over, then just fire and never miss a beat. No miss, sputter or anything like that. That's what dad keeps saying.... "it's like you just reach down and flip a switch on"

 

[Mdub707]

I only suggested pulling the IPR for a visual inspection, not necessarily replacement. It may be sticking. The numbers just don't make sense.

We know it needs 500psi of ICP (actual) to even fire.

Typically a good running truck will idle at ~525-600psi of ICP, with IPR being in the 25% range.

I have seen trucks with weak batteries and weak FICM's raise ICP to try and overcome the weak pull on the injectors. I fixed a FICM for a local guy, his truck would start rough as hell, idle ICP was at 1200 or so, IPR was at 35-40%... swapped a good unit on and it dropped right down to normal numbers too. Might be something else to check out. I don't think it's all of your problem, but may be a part of it. I would still pull the IPR if nothing else for a visual.

 

[6speedsd]

Oh I will pull it when I go to try and find that leak. Just no time right now. I had to go pull him home today in it...top of the radiator cracked around the inlet neck. Was spraying antifreeze everywhere. Not sure why it just randomly cracked.


Sent from my iPhone using Tapatalk